s1_generate_a_series_of_files(){
for index in {1..100}; do
	echo -n "$index" > "/tmp/new_files$index"
done
}
s2_list_4_files_in_long_format_account_and_group(){
ls -L /etc/passwd /etc/group /etc/shadow /etc/gshadow | sort
}
s3_find_items_related_to_given_username(){
grep "^$1:" /etc/passwd /etc/shadow | sort
}
s4_find_items_related_to_given_group_name(){
grep "^$1:" /etc/group /etc/gshadow | sort
}
s5_create_groups_for_given_group_names(){
groupadd rnd
groupadd itoperation
}
s6_create_users_and_set_their_group_as_required() {
useradd -m -G rnd adam
useradd -m -G rnd bob
useradd -m -G itoperation calvin
useradd -m -G itoperation david
useradd -m -G rnd edward
}
s7_change_users_shell() {
chsh -s /usr/bin/sh adam
chsh -s/usr/bin/sh edward
}
s8_set_password_change_policy() {
for user in adam bob calvin david edward; do
	change -m 10 -M -W 10 "$user"
done
}
s9_set_password_for_five_users() {
	local users=("adam" "bob" "calvin" "david" "edward")
	for i in {0..4}; do
		echo "${users[$i]}:${!((i+1))}"
	done | chpasswd
}

s10_lock_bobs_password() {
passwd -1 bob
}
s11_include_adam_into_wheel_group() {
usermod -aG wheel adam
}
s12_change_files_permission() {
	for index in $(seq 3 3 99); do
		chmod 640 "/tmp/new_file$index"
	done
}

